Keep in mind that sales teams are there to ... sell the product you wrote. They are naturally adapting to client demand and selling features that their (and yours!) clients need. You actually want them doing this; it means that revenue is coming in the door and that your product is staying relevant to market needs.
I'll note that this can be related to vapor-ware, in which things are promised and promised but never delivered. But there's a nuance behind that term that's not applicable to your question.
It's only an issue when delivery schedules aren't clearly defined or when the sales team over-promises on what can be delivered. And while this creates stress for the developers involved in implementing those visions, ultimately it isn't their issue to resolve. Upper management and product development management needs to work with the sales management to define when features can be advertised for sale and what schedules can be committed to. Over-commitment tarnishes the company's image and is rightfully an issue for upper management to resolve.
Generally speaking, Developers (and Sales...) like to see a
Design => Sell => Develop approach to sales and marketing. Development has an idea of what might be flogged to the potential clients and Sales has an idea of when idea
XYZ could actually be delivered if the potential client is interested.
There are cases where you'll see
Sell => Design => Build, and this path is more likely to cause problems for the development team. On the one hand, if the Sales team really understands the code base* then this can be an effective route to new contracts. On the other hand, there is a greater chance to over-promise what can actually be delivered in a reasonable period of time. Your question calls out some of the keys in determining how well this approach will work out.
*Yes, I know the cynical reply of "that never happens." But it can occur when one of the founders of a firm was highly technical and has moved into a role driving more sales. There is also whole branch of "Technical Sales" personnel as well.